/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.activiti.engine.impl.cmd;

import java.io.Serializable;

import org.activiti.engine.delegate.event.impl.ActivitiEventBuilder;
import org.activiti.engine.impl.interceptor.Command;
import org.activiti.engine.impl.interceptor.CommandContext;
import org.activiti.engine.impl.persistence.entity.AttachmentEntity;
import org.activiti.engine.impl.persistence.entity.ExecutionEntity;
import org.flowable.common.engine.api.delegate.event.FlowableEngineEventType;
import org.flowable.common.engine.impl.interceptor.EngineConfigurationConstants;

/**
 * @author Tom Baeyens
 * @author Joram Barrez
 */
public class DeleteAttachmentCmd implements Command<Object>, Serializable {

    private static final long serialVersionUID = 1L;
    protected String attachmentId;

    public DeleteAttachmentCmd(String attachmentId) {
        this.attachmentId = attachmentId;
    }

    @Override
    public Object execute(CommandContext commandContext) {
        AttachmentEntity attachment = commandContext
                .getDbSqlSession()
                .selectById(AttachmentEntity.class, attachmentId);

        commandContext
                .getDbSqlSession()
                .delete(attachment);

        if (attachment.getContentId() != null) {
            commandContext
                    .getByteArrayEntityManager()
                    .deleteByteArrayById(attachment.getContentId());
        }

        if (attachment.getTaskId() != null) {
            commandContext.getHistoryManager()
                    .createAttachmentComment(attachment.getTaskId(), attachment.getProcessInstanceId(), attachment.getName(), false);
        }

        if (commandContext.getProcessEngineConfiguration().getEventDispatcher().isEnabled()) {
            // Forced to fetch the process-instance to associate the right process definition
            String processDefinitionId = null;
            String processInstanceId = attachment.getProcessInstanceId();
            if (attachment.getProcessInstanceId() != null) {
                ExecutionEntity process = commandContext.getExecutionEntityManager().findExecutionById(processInstanceId);
                if (process != null) {
                    processDefinitionId = process.getProcessDefinitionId();
                }
            }
            commandContext.getProcessEngineConfiguration().getEventDispatcher().dispatchEvent(
                    ActivitiEventBuilder.createEntityEvent(FlowableEngineEventType.ENTITY_DELETED, 
                            attachment, processInstanceId, processInstanceId, processDefinitionId),
                    EngineConfigurationConstants.KEY_PROCESS_ENGINE_CONFIG);
        }
        return null;
    }

}
